This is too small a deal for "major MHP lenders." Your best bet is to try to get seller financing, and next best is a local bank (especially the one where the seller is parking the rents). The local bank rates now are in the 4.5% to 4.75% with 75% LTV and 5 to 7 year term on 20 to 30 year amortization. Let us know what you found.

Security Mortgage Group will do $500K+ loans. Frank recommends them in other threads - would call them first as they understand MHP's. And agree Owner Financing would be good if the loan and terms are competitive. Last resort investing a bunch of time peppering local banks to see who is interested.